Method of broaching rotating work



May 22, 1951 w. L. GROENE 2,553,966

METHOD OF BROACHING ROTATING WORK Fiied March 29, 1949 s $heetsSheet 1WORK RAZ D 13 1?; 15 ROTATION G1 TRAvERsE l- E E 15 FEED g5 DWELL\\7OC g13 DWELL/ 13C 12 FEED :1 EH31 RAPID 70b 2 15 TRAVERSE 15a WORK ROTATIONB H l? F G. Fl 6. 3

IN VEN TOR.

May 22, 1951 w. GROENE METHOD OF BROACHING ROTATING WORK 3 Sheeis-Sheet2 Filed March 29, 1949 INVENTOR.

y 22, 1951 w. GROENE 2,553,966

- Filed March 29, 1949 '5 Sheets-Sheet 5 METHOD OF BROACHING ROTATINGWORK IN V EN TOR Patented May 22, 1951 UNITED STATES PATENT OFFICE2,553,966 MET OD O BRQA H G ROTATING WORK Willard L Groene, Phoenix,Ariz., assignor to The R 'K. 'LeBlond 'Machirie Tool 00., Cincinnati,Ohio, a corporation ofDelaware Appl cation March 2 ,9, S rial q- $4 ,45, 7 Clai ns. (01. 90-?33) This invention pertains to an improved methodof prea hi g rotating work' "More particularly this invention pertainsto a rnetal working pro- Qedure in which a series of cutting edges ofthe cutting tool are rapidly and successively pre s'ente t an Wi hd wn fom cu ng P s ti n relative to a workpiece rotating rapidly at a cut inss eed: I

Que of thev Qbissts of this inv n ion is to. prov de a ms h d'by Wh hi sss of i e e n. sussss i s ess t tisn sh cu o t of a smas i m sting w rke e s eliminated. 221 t thu eve th non-c tt ng t m in. t machin n c cAnsther Qb st Qt th m tho is t m ke s- .391 th use of much h her c tti gspee s by on y a l w n a u ng ed o he cutti g P r brosh o r main isuitin s e w th ork 9 a mal int rval s t me! s d n to epl ce t imm di tey W t ou l s 'Q suiting time, w h other u tin d s successively P se sedo'cu bing p it sm- A s hs bisss 1 this ven i i t pss s a m th o la ssntins' iss s u i edges s s b h t t e Ps in sr s m st g Workss? i an nrmit e t mens? 'tbst sash ot ms s s rsaiq r v se su i P951" isn c ieus mas s sd i Wh in utt n pss i nz s i l t9 m ntsr ly p d we l a he lnslsisn o t litt Operation, and then to present the next and successiveteeth s? th s m msn r Stil n he s is 9f h in s q i to p s s a ms h l s es snsi s 's of s ss broached teeth of a broa 't a ta n wore s s'by' heii srin ts t em m th r s h s v able ra es of o ements dwell i timed slass his is hi ees- 's s pitch of h e h peg 9h fu he o j ct. .o thi i entin s o pr v de seri s s t in ed s about the peripher f a broachingcutter, and to rotate'the cutter'at intermediate variable rates ofrotation'and dwell la i s s wsr isisss r at n s'li fii s d it is also anobject to cause a relative in feeding rnovernent between the axis ofrotation of the broach cutter and the rotating'workpiece during saidintermittent rotary movement of the out tgg ei s o: ihe r' sh s sFurther features'and advantages oi this invention Wiil appear froin thefollowing detailed description fthe drawings which:

Figure l is an enlarged diagrammatic view hswins thi r lati n i i f i hn's it s h .r tsti sis-eis fl ki s s sfii'fi in 2 which the work surfaceand broach teeth mov la e y in opposite directio s,

FigureZ is a circuit diagram of a hydraulic and electrical circuitadapted to effect the relative intermittent motionei the work andbroach." Figure 3" is a diagram similar to Figure 1', showing therelationship of work and breach where the werk' and b roach' rnove'relatively to each otherin the samedirectio'nl Figure 4 is an enlargediragrnentary View of a portion of the control eam shewn in Figure 2 forcgntrolling the breach movement during'the ini tial stages oi thecuttingcycle; Figure 5 is' an enlarged jragrnentary view of the control cam forcentrdliing 'the'broach movei'nent during the'final stages ofthe'cutting eyclel Figure 6 is a diagrammatic view showing an ariafigenent'in rotary breaching utter uti z d v. v .r .e V A .r

Figure 7 is a view of the driving and control mechanism for the rotarybroach arrangement, nd s' ts y he l ne ll-f s i ur one form of inventionthere is utilized as St gh mafl l wh i m ved i tangential rapid traverseand feeding movements indicated hy'the l ne I l. A'seriejg gfbroaehteethI? are jor'r'nd' on the breach to so that their cutting edges l3 are disosed in a plane M which is slightly angularly related to the directionof feeding movenient I I so that each cuttingedge ['3 successivelyprojeets' outwardly toward the'vvorl; surlace being] inachined "fromeach preceding memes the hroach is fed ina'direetion indicated by thearrow I5. The workpiece W having the eylindric'al work surface l6 tobemachined,"is rotated at a relativelv'rapid cutting speed. In thisarrangement the peripheral or surface speed of'the surface I6 is asgreat as or' considerflabl'y above well accepted standards'for surfacespeeds in chi e pp gre H q v ,g 'In prior apparatus of this kind it hasbeen the nractice to feed the broach 10 at a uniformcgn tinuous'movement while presentingthe' putting edges to the work surfacedfi, Inthisinvention,

Q s e i is t bi s t i erm ts l aryc the rate of 'lfeedingni'ove nent andto'eause a dwell pr stopping 6i this motion in relationship to eachcuttingtooth presented to the workpiece} Forinstance,'takingthe'cuttingedge I34 Figure 1, is positioned as indicated by the line H, the broachL0 is first movedat E g y rapid traverse movement to Quickly bring thecuttingedge [312 rapidly to the position lglj indicated by the line I 8;at which point'the cutting edge begir is'- to ens gage and 'eut' theworksiiriace'i fi. At this point the broach movement indicated by the arrowI5 is reduced to a slow feed rate while it continues to cut the worksurface |6 until it feeds down to the position |3c indicated by the lineH3, at which point further cutting action of the tooth ceases. At thispoint the broach I is stopped in motion and the cutting edge allowed todwell at |3c during at least one complete revolution of the work surface|6 so as to complete a true cylindrical diameter on the workpiece beforeproceeding with the presentation of the next cutting tooth edge to thework in a manner just described for the cutting edge I311. The steppedpositioning of the cutting edges l3 in the plane I4 provides thenecessary radial in-feeding of the cutting edges relative to the axis ofrotation 28 of the work W.

The aforementioned rapid traverse, feed, and dwell for the broachmovement I5 is accomplished automatically, for example, by anarrangement shown in-Figure 2. In this arrangement there is provided ahydraulic motor or cylinder 2| in which is reciprocatably mounted thepiston 22 having a piston rod 23 rigidly connected through a suitableconnecting means 24 to an arm 25 fixed to the broach l0 so thatreciprocation of the piston 22 in the cylinder 2| effects similarreciprocation of the broach I8. Also connected to be moved with thepiston 22 and the broach I0 is the control cam 26 having a suitableconnection 21 with the arm 25 of the broach In. The piston 22 isactuated by fluid pressure derived from a rapid traverse pump RT and avariable delivery feed pump VD, each receiving a supply of hydraulicfluid through the respective suction lines 28 and 29 from the fluidreservoir 38.

At the beginning of the cutting cycle the tip 3| of the plunger 32 ofthe control switch 33 is located on one of the high points or lands 34of the control cam 26, Figure 4, so that its switch bar 35 interconnectsthe lead 36 to the lead 3! to cause current from the supply lead Ll tobe connected to the solenoid 38 of the valve 39 and to the solenoid 40of the valve 4|, the return lead 42 completing the circuit back to theother supply lead L2. When solenoid 40 of valve 4| is thus energized,fluid supply from the rapid traverse pump RT passes through the line 43into the line 44 and through the ball check valve 45 to the line 46connected to the forward feed chamber 4! of the cylinder 2|. The returnchamber 48 of the cylinder 2| is connected for discharge of fluidthrough the line 49, and then freely through the stop or dwell valve 50which has its solenoid 5| de-energized at this time so that the valve isopen. The flow from the open valve 50 passes through the line 5|a to thevalve 39 which is open at this time because its solenoid 38 is energizedallowing the fluid to pass into the drain line 52 for the return offluid to the reservoir 30.

The manually operated control valve 53 is set at this time so that fluidpressure from the variable delivery pump VD is connected from the line54 to the line 55 which in turn is connected to the line 46 so as tocontinuously supply the chamber 41 of the cylinder 2| from the variabledelivery pump VD. As the rapid traverse movement of the broachcontinues, the plunger 32 of the control switch 33 drops down on to theintermediate land 56, Figure 4, of the control cam 26 to thus disconnectlead 36 from lead 31 which de-energizes solenoid 40 of valve 4| to cutoff the supply from the rapid traverse pump RT and connect the line 43to the drain line 51 for return of the rapid traverse pump fluid to thereservoir 38. The solenoid 38 of the valve 39 is also deenergizedcutting off discharge of fluid from the line 5m to the line 52 andcausing this flow to now take place through the feed rate control valveFR into line 58 which is connected through the valve 53 to the drainline 52.

During the initial diameter reducing cutting stages between points A andB of the broach, Figure 2, where the teeth are arranged in steppedposition in a plane indicated by the line I4, it may not be necessary toutilize the dwell of the cutting edges of the broach teeth at theposition I30, in which case the plunger 32 of the control switch 33again is brought up on the next high surface 340, of the cam 26, Figure4, to again cause the rapid traverse movement of the broach to presentthe next cutting tooth into cutting position as described. Theaforementioned operating cycle of rapid traverse and feed movement ofthe broach l0 continues in timed relationship with the position andspacing of the broach teeth by arranging the position of the controlsurfaces 34 and 56 of the cam 26 with the same spacing and in properposition relative to the teeth of the broach and the plunger 32 of thecontrol switch 33.

In certain cases it is desirable to also utilize a dwell at theconclusion of each feed movement of a broach tooth before proceeding atrapid traverse to present the next tooth, this dwell continuingsufficiently long enough for the Work to have rotated at least one orslightly more than.

one complete revolution with the cutting edge of the broach tooth in theposition |3c. This is particularly desirable on that portion of thebroach between the points B and C where the cutting edges of the broachteeth are all located.

in the same plane I a parallel to the line of feeding When this portionof the broach is applied to the work there is provided a still deeper.

notch 59, Figure 5, in the cam 26 which causes the plunger 32 of thecontrol switch 33 to bring.

the switch bar 60 into contact so as to connect lead 36 to lead 6|. Lead6| is connected through a manually operated disconnect switch 62connected by a lead 63 to a timer 64 which is connected through a lead65 to the solenoid 5| of the stop valve 58, which in turn is connectedthrough a lead 66 and the lead 42 to complete the electrical circuit.Energizing the solenoid 5| causes the valve 59 to close off the line 49so as to trap the fluid in the chamber 48 of the cylinder 2| to thushold the broach l0 against movement for the dwell. The length of thedwell is determined by the setting of the timer 64 and after apredetermined interval, set so as to be suflicient to allow at least onecomplete revolution of the workpiece, it opens the circuit between theleads 63 and 65 to de-energize the solenoid 5| to again open the valve50 for free flow of fluid between V the lines 49 and 5|a.

The cam surfaces at D, Figure 2, may be made as shown in Figure 5, toaccomplish the dwell for the teeth of the portion B to C of the broachl8 while the remaining portion of the cam surfaces may be arranged asshown in Figure 4. Another way is to make the entire cam with surfacesas in Figure 5, and to utilize the cut-out switch 62, either manuallyoperated or controlled from the movement of the cam 26 in any well knownmanner, to cut in or cut out the dwell function at any point in thecutting cycle.

The broach is returned to initial starting position at the conclusion ofthe cutting cycle by manipulating the valve. 531 so. as to connect ra idt averse pump pressu e from. th line 4.3 throu the line 61 to the line58 from which it. passes through the. ball ch ck 68. the line 5w. r ythrough the valve 50, through the 'line 49 into the return chamber 48 ofthe cylinder 2|. Discharge from the chamber 41 of the cylinder 2| passesthrough the line 46 and the line 5.5 throughthe valve 53 to the drainline 52.. I

The aforementioned principles. of actuating the broach H1 at rapidtraverse, feed, and dwell in relationship to the broach teeth is welladapted to an arrangement such as shown in Figure 3, in which the broachmovement indicated by the arrow IEa, takes place in the same directionas the rotation of the work surface I6. Since the work surface [6 isrotating at a rapid cutting speed, the work surface overtakes thecutting edges of the breach so that during the feeding motion of thebroach a cutting of the work surface is accomplished. The cutting teeth69, having cutting edges it, move in a line of feeding movement 7| withtheir cutting edges located in stepped position as indicated by the line12. By utilizing the arrangement of Figure 2, the cutting edge 10a movesat rapid traverse movement to position 70b and at feed movement toposition 100 where the dwell may then be effected as desired.

Still another arrangement utilizing the principles of this invention isthat shown in Figures 6 and 7, wherein the broach teeth 13 are arrangedeccentrically around the periphery of a circular or rotary broach cutterN30. The cutter lilo is mounted for rotation about an axis 14 on a shaft15 to which is fixed a gear l6 which in turn is driven from a pinion Hon the shaft 18 of the hydraulic motor 2 I a, this motor being connectedin the circuit of Figure 2, the same as the cylinder 2!. By controllingthe fluid motor Zia. the cutter lllc is intermittently rotated at rapidtraverse, feed, and dwell in timed relationship to the pitch or spacingof the cutting teeth 13. In this arrangement the control cam 26 ofFigure 2 takes the form of a circular cam 26a fixed to the shaft l5 soas to rotate with the cutter I00. The same cam configurations 19 arearranged about the periphery of the cam 26a so as to appropriatelyactuate the control switch 33 to perform the functions as described.

In this arrangement of the circular cutter with the concentricallyarranged teeth I3, the pro-- gressive relative radial in-feed of workand tool is accomplished by moving the axes 20 and '14 of the work W andthe broach cutter I90 toward each other as indicated by the arrow 80.This movement continuously takes place until the proper diameter for thework surface is reached, at which time and by apparatus of well knowncharacter, the in-feed movement is stopped and the cutting teeth 13 arestopped at dwell position so as to finish size work to correctconcentric diameter. In this arrangement, of course, the work isrotating at a rapid cutting speed in a direction as indicated by thearrow 31 and the cutter lEic may be rotated in either direction toaccomplish the desired intermittent rapid traverse, feed, and dwellmovements for the cutting teeth in timed relation to their spacingaround the periphery of the cutter.

Having thus fully set forth and described this invention what is claimedand desired to be secured by United States Letters Patent is:

1. The method of broaching rotating work comprising, rotating aworkpiece about an axis at a rapid cutting speed, m ving in a, step.-.bystep manner a series of cutting edges. lying parale lel to saidaxis relative to a work surface of said workpiece in a directiontangentially to said work surface, presenting said cutting edges into acut-. ting position relative to. the work surface by mov-. ing each ofsaid cutting edges, first at a rapid traverse movement to begin itscutting operation, and then in a slower feed movement to complete thecutting operation.

2. The method of broaching rotating work comprising, rotating aworkpiece about an axis at a rapid cutting speed, intermittently movinga series of cutting edges lying parallel to said axis relative to a worksurface of said workpiece with a step-by-step movement in a directiontangentially of said work surface, presenting said cutting edges intocutting position in a plane passing through said axis and perpendicularto said direction of tangential movement relative to the work surface bymoving each of said cutting edges, first at a rapid traverse movement tobegin its cutting operation, and then in a slower feed movement, andfinally holding said cutting edge in dwell at the completion of itscutting operation during at least one complete revolution of theworkpiece. Y

3. The method of broaching a rotating cylindrical workpiece comprising,rotating the workpiece surface about an axis at a rapid cutting speed,moving a series of stepped broach teeth cutting edges positionedparallel to said axis in a line of feeding movement tangentially of thework surface, and intermittently actuating said series of cutting edgesin rapid traverse and slower feed movements in a predetermined timedrelationship to the position of each successive broach tooth cuttingedge relative to a plane passing through said axis perpendicular to saidline of tangential feeding movement.

4. The method of broaching a rotating cylindrical workpiece comprising,rotating the workpiece surface at a rapid cutting speed, intermittentlymoving a broach comprising a series of stepped broach teeth havingcutting edges located parallel to the axis of rotation of said workpiecein a line of feeding movement tangentially of the work surface byactuating said broach at a rapid traverse and a slower feed and dwellmovements in timed relationship to the position of each successivebroach tooth cutting edge relative to said workpiece axis.

5. A method of broaching rotating work comprising, rotating a workpieceat a rapid cutting speed, intermittently moving a series of broach teethwith cutting edges parallel to the axis of rotation of the workpiecetangentially to and in the opposite direction to the rotation of thework surface to be machined, and actuating said broach teeth so as tosuccessively present said cutting edges at a rapid traverse rate tocutting position, and at a slower feed rate to complete the cuttingoperation, in a timed relationship to the position of each successivecutting edge relative to the workpiece.

'6. The method of broaching rotating work comprising, rapidly rotating acylindrical workpiece at a cutting speed, intermittently tangentiallypresenting a series of cutting teeth having cutting edges parallel tothe axis of rotation of the workpiece by movement in the same directionas the direction of rotation of the work surface being machined, saidlast mentioned movement being performed at a rapid traverse, a slowerfeed, and dwell movement in a predetermined timed relationship to thespaced position of each successive cutting tooth relative to theworkpiece.

'7. The method of broaching rotating work comprising, rotating aworkpiece at a rapid cutting speed, moving a series of broach teethhaving cutting edges parallel to the axis of rotation of said workpiecein a circular path relative to the work surface to be machined withintermittent rapid traverse, slower feed, and dwell movements in timedrelationship to the spacing of said cutting edges of said teeth in saidcircular path; and causing relative movement between said axis ofrotation of the work and the axis of rotation of the circular path ofmovement of said 15 broach teeth.

WILLARD L. GROENE.

8, REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 482,211 Tucker Sept. 6, 18922,044,494 Bullard June 16, 1936 2,044,495 Bullard June 16, 1936 H)2,233,399 Carlin Mar. 4, 1941 2,362,318 Staples NOV. 7, 1944

